Supervised electrical alarm



Jan. 15, 1952 NEWELL 2,582,790

SUPERVISED ELECTR I CAL ALARM F1136. Oct. 25, 1948 2 SHEETS-SHEET 1 Inventor: HebePLNewell,

His Abborney Jan. 15, 1952 H. L. NEWELL SUPERVISED ELECTRICAL ALARM 2 SHEETS-SHEET 2 Filed 001:. 23. 1948 Fig. 5.

Inventor. Hebevr L.Nevvell 13 Zf y His Abborngy.

Patented Jan. 15, 1952 SUPERVISED ELECTRICAL ALARM Heber L. Newell, Malvern, N. Y.,- assignor to General Electric Company, a corporation of New York Application October 23, 1948, Serial N 0. 56,084

5 Claims. 177-311) My invention relates to alarms and more particularly to solenoid-operated alarms.

It is an object of my invention to provide an improved alarm for indicating abnormal conditions.

It is another object of my invention to provide an improved alarm for indicating undesirably high temperatures.

It is a further object of my invention to provide an alarm including an improved arrangement for indicating when the alarm is not in proper condition for operation.

It is still another object of my invention to provide an improved alarm adapted to be plugged into an ordinary household electrical outlet.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

For a better understanding of my invention, reference may be had to the accompanying drawings in which Fig. 1 is a front elevation view, partly in section, of an alarm embodying my invention; Fig. 2 is a side elevation view, partly in section, of the alarm shown in Fig. 1; Fig. 3 is a sideelevation view of a modified form of my invention; Fig. 4 is a front elevation view, partly in section, of a portion of the form shown in Fig. 3; Fig. 5 is a side elevation view, partly in section, of another modified form of my invention; Fig. 6 is a sectional view taken along the line 6-t of Fig. 5; and Fig. '7 is a perspective view of a portion of an alarm showing still another modified form of my invention.

One application of my alarm is for indicating undesirably high temperatures in a cabinet used for storing frozen food, so that prompt action may be taken to prevent spoilage of the food. The alarm will be described in connection with such a use.

Referring now to Figs. 1 and 2, there isshown an alarm including a base I formed of suitable electrical insulating material. A supporting bracket 2 is secured to the base I by rivets 3 or other suitable fastening devices. A pair of solenoids 4 and 5 are mounted on the supporting bracket 2 with their axes in aligned relationship. The solenoid 4 is secured to the bracket 2 by a screw 6 or other suitable fastening device and the solenoid 5 is similarly secured to the bracket by a screw 1.

The solenoid 4 includes a core 8 of easily mage netizable material, such as iron, surrounded by 2 a coil 9 composed of a suitable number of turns of insulated wire. The solenoid 5 similarly includes a core I0 surrounded by a coil II. A

vibratory element or reed I2 extends transverse:

1y of the axis of the solenoids l, 5 and is disposed midway of the gap between the opposed faces of the cores 8 and I0 of these solenoids. This reed is adapted to be vibrated by either of the solenoids 4 or 5 when energy is supplied to such solenoid from an alternating current power source. The reed I2 is mounted on a support I3 which is secured, by welding or other suitable method, to the supporting bracket 2. The supporting bracket 2 and the support I3 contain aligned openings I4, which are threaded to receive a screw I5. A cover I6 for the alarm structure is held in place by the screw I5 which passes through an opening in the cover and engages the threaded openings I4. The cover is spaced from the solenoids by spacers I'I, I8.

The alarm structure is constructed so as to be received within an ordinary two-receptacle household electrical outlet I9. Power is supplied to the outlet I9 from an alternating current power source through a conventional electrical circuit includinga fuse (not shown). In order to facilitate such mounting, a plurality of prongs or terminals 20, 2| are secured to the base I by rivets 22, 23 or other suitable fastening devices. The prongs '20, 21 are spaced so as to fit within corresponding receptacles of the two-receptacle outlet. The prongs 2B are dummy prongs for.

assisting in maintainingthe alarm in engagement'with the outlet, and are not intended to transmit power to the alarm. The prongs 2I are arranged to supply power from the electrical outlet to the solenoid 5. The prongs 2| are connected by leads 24, 25 to terminals 26 and 21, respectively, mounted on the base I. From the terminals, current is transmitted to the solenoid 5 through leads 28, 29. In order that the outlet may still be available for other electrical devices, even though the face is covered by the alarm,

- a utility receptacle 3B is secured to the bottom portion of the cover l6. Power is supplied to.

second electrical circuit including lines 34, 35. This second circuit, like the circuit for supplying the outlet I9, includes a conventional fuse (not shown), separate fuses being provided for these The resceptacle 3B two circuits. The lines 34, 35 are connected to terminals 36, 31 respectively, which are mounted on the base I of the alarm. The solenoid 4 is connected to these terminals through leads 39. Power to the solenoid 4 is controlled by a temperature-responsive device in response to the temperature within a freezer cabinet. This device includes a thermostatic bulb 40 which is adapted to be received within a freezer cabinet (not shown) so as to be affected by the temperature within the cabinet. The bulb 40 is connected by a tube 4| to a bellows 42. The bellows, upon expansion and contraction, opens and closes a switch 43 for controlling the power supply to the solenoid 4. The temperatureresponsive device is arranged so that when a satisfactory low temperature is maintained within the freezer cabinet, the switch 43 is held in its closed position; when the temperature within the freezer compartment increases above a predetermined maximum, the bellows expands to open' the switch and cut off the supply of power to the solenoid 4.

The operation of the alarm is as follows. Powder isnormally supplied to the solenoid 4 from the alternating current source of supply through one circuit controlled by the temperature-responsive device of the freezer. Power is supplied to the solenoid from the alternating current source through a second circuit including the receptacle l9. These two circuits are separately, fused so that the blowingof a single fuse will not cut out both of the circuits. The forces exerted on the reed by the solenoids 4 and 5 are substantially equaland, under normal operation, vthe'reed I2 is maintained stationary because of the equal opposing forces exerted on the'reed by these solenoids. While, for convenience, astep-down transformer may be included in the circuit of the solenoid 4 so as to reduce the voltage across the contacts of the switch 43, the relative number of turns of wire of thev solenoids 4 and 5 are chosen so that the magnetomotive forces exerted by the two solenoids are equal. Should the temperature within the freezer cabinet rise above the predetermined maximum, the power supplied to the solenoid 4 -is interrupted by the opening of the switch 43. The reed I2 is then acted on only by the unopposed magnetomotive force exerted by the solenoid 5 and the reed is caused to vibrate, giving off a buzzing sound to indicate to the householder unsatisfactory operation of the freezer." If desired, two projections 44, 45 may be secure-d to the inside of the cover 16 in a position' to be engaged by the vibrating reed I2 so as to amplify the sound of the alarm.

It is possible that for some reason the fuse in the circuit supplying power to the solenoid 5 might blow thereby deenergizing this solenoid and hence causing failure of the alarm to sound when the solenoid 4 is deenergized by excessively high temperature within the freezer cabinet. However, by my arrangement, such failure of the circuit of the solenoid 5 is prevented from going unnoticed. Thus, should the supply circuit to the solenoid 5 become broken for any reason, the reed I2 is subjected to the unopposed magnetomotive force exerted by the solenoid 4, and the reed is caused to vibrate, sounding an alarm in the same manner as described above in connection with excessively high temperatures of the freezer cabinet. Hence, if upon the sounding of the alarm, the householder finds that the temperature of the cabinet is satisfactory, he can immediately correct the defect in the power supply of the solenoid 5, insuring satisfactory operation of the alarm at all times.

My alarm structure has an additional advantage in that it does not sound should both the solenoids 4 and 5 be deenergized. It often happens that the entire power supply of an area is cut out for a short period. Since the freezer can hold satisfactory low temperatures for a period of about 24 hours, it is undesirable, should such general power failure occur during the middle of the night, for the householder to be disturbed by the sound of an alarm. If the situation has not been corrected by morning, the general power failure Will be immediately apparent by the stopping of electric clocks and the failure of lights or other electrical devices to operate. Thus, the alarm is assured of operation under all conditions where such operation is necessary, but the sounding of the alarm is prevented where such operation would be of only nuisance value.

In Figs. 3 and 4 there is shown a modified form of my invention which is suitable for mounting on a fiat wall in lieu of the convenience outlet mounting arrangement illustrated in Figs. 1 and indicate corresponding parts in all of these figures. As shown most clearly in Fig. 3, the alarm is secured to a wall or other flat surface 46 by screws 41, 48 or other suitable fastening devices,"

which pass through openings in the base i of the alarm and into threaded engagement with the wall 46. The prongs 20, 2| are omitted from the modified form shown in Figs. 3 and 4. This form may be specifically constructed with the prongs omitted. Alternatively, however, the prongs on the form illustrated in Figs. 1 and 2 may be broken off adjacent the top of the outer surface of the base I by bending the prongs back and forth with a tool, such as pliers.

In order to supply power to the solenoid 5 in this modified form, leads 49 and 50 are provided from the alternating current source of supply and are connected to terminal blocks 26 and 21 respectively of the alarm. The leads 49, 50 pass through openings in the cover I6 and grommets 5|, 52 of rubber or other electrical insulating material are provided between the leads and the cover.

In Figs. 5 and 6, there is illustrated another modified form of my invention in which the alarm is shaped to extend within an electrical outlet box and is provided with a single pair of prongs for reception within a receptacle associated with the outlet box. The structure illustrated includes an outlet box 53 mounted within a wall '54. An outlet structure including a flanged metal element 55 and an insulating portion '56 is secured to the outlet box by screws 51, 5B. The insulating portion 56 includes two electrical receptacles 59 and 60. The receptacle 60 corresponds to the receptacle 30 in the forms previously described and is utilized to provide power for any electrical devices. The alarm structure includes an outer wall 6| formed of suitable electrical insulating material. The wall 6| includes a portion 62 which is adapted to fit snugly within a chamber 63 formed within the outlet structure. The alarm includes a pair of solenoids 4 and 5 which are positioned by screws 63 passing through openings in the wall 6|. A vibratory element or reed I2 is arranged between the solenoidsand the end of the reed is adapted to strike against a projection 44'. In this form a bell 64 is used to impart a ringing sound to the alarm, and the projection 44' is secured to the inner surface'oi the bell E4. The bell E lis supported on the screws 63' by a bracket 64, the bell being secured to the bracket by'a bolt and nut 65.

Power is supplied to the solenoid 5 from the receptacle 59 through two prongs or terminals 65, only one of which is shown in Fig. 5. Two leads 28, 29 are connected between the prongs 65' and the solenoid 5'. Power is supplied to the solenoid 4 through-leads '34, 35 in the same manner as in the previously-described forms of this invention. The operation of the alarm shown in Figs. 5 and 6 is the same as that described in detail in connection with Figs. 1 and 2.

Another form of my invention is shown in Fig. 7. Only the details of the sounding mechanism are shown in this figure, but it will be apparent that these elements may be combined in an overall structure similar to that illustrated in any of the preceding figures. Referring now to Fig. 7, the alarm illustrated includes a base structurefifi. Two supporting elements 61, 68 are secured to opposite ends of the base 66. A solenoid 69 is mounted on the supporting element 61. This solenoid is illustrated schematically and includes a core in of suitable magnetizable material and a winding II. A similar solenoid 12'is mounted on a supporting element 68. This solenoid includes a magnetizable core 73 and a winding 14. An uprgiht portion E5 of a supporting element 68 is provided with a slot 16, and a vibratory element or armature ll is pivotally mounted within the slot 16. A corresponding vibratory element or armature i8 is mounted within a slot 19 in an upright portion 15 of the Supporting element 61. The armatures l1 and 18 include extended portions 80, 8| respectively which are bent slightly upwardly from the plane of the remainder of each of the armatures. These extended portions 80, BI are connected by a spring 82 which holds the armatures in position against the upright portions 15 and 15 and also biases each of the armatures away from its corresponding solenoid. The two armatures 11, 18 are interlocked by overlapping arms 83, 84, and 85, 86 so as to prevent vibration of either when both solenoids 69 and '52 are energized. A depending striker 81 is secured to the arm 83 and a corresponding striker 88 is secured to the arm 85. Each of these strikers is adapted upon vibration of the armature with which it is associated, to strike a sounding plate 89 to give an alarm indication.

As in the forms previously described, one of the solenoids, for example, solenoid 69, is supplied from an alternating current source through a first circuit including a switch controlled by a temperature-responsive device associated with a freezer cabinet and the other solenoid, for example, solenoid i2, is supplied from the alternating current source through a second, separately-fused circuit. When both solenoids are energized the armatures or vibratory elements I1, 18 mutually prevent vibration because of the overlapping arms 83, 84 and 35, 86. Thus, when the armature H is pulled into engagement with the core 13 because of energization of the solenoid 12, the arm 84 is forced upwardly into engagement with the arm 83 of the armature .8, and'vibration of the armature 18 is prevented. Similarly, when solenoid 69 is energized the arm 86 engages the underside of the arm and prevents vibration of the armature 11.

Should the solenoid 69 become deenergized because of the breaking of the first circuit by the temperature-responsive device as a result of an excessively high temperature in the freezer cabinet, the armature I8 is pulled away from the solenoid 69 by the spring 82, because of the upwardly extending construction of the portion SI of the armature. The arm 86 is thereby moved downwardly out of engagement with the arm 85 of the armature 11. The armature TI is enabled to vibrate under the influence of the alternating current solenoid I2 and this vibration is translated through the striker 8'! and the sounding plate 89 into an alarm sound, Warning of the high temperature in the freezer cabinet. Similarly, should the fuse of the second circuit blow. deenergizing the solenoid 12, the arm 84 is moved out of engagement with the arm 83 of the armature l8, and the striker 81 is enabled to strike the sounding plate 89. to give an alarm sound. Should both solenoids become deenergized simultaneously because of a general power failure, for example, no alarm is sounded.

While the foregoing description has been directed primarily to the use of this alarm with freezers to indicate undesirably high temperatures, it will be apparent that the alarm can be used equally well to indicate other abnormal conditions. For example, the switch 42 in Fig. 1 could be operated by a pressure-responsive device so that the alarm would indicate abnormally high or abnormally low pressures, or the switch could be operated by a speed-responsive device, in which case thealarm" would indicate abnormally high or abnormally low speeds. I intend, by the appended claims, to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An alarm comprising a first solenoid adapted to be energized from a first electrical circuit, a second solenoid adapted to be energized from a second electrical circuit, said first circuit and said second circuit being separately fused, a vibratory element positioned for actuation by said first solenoid, said second solenoid exertin a force on said vibratory element opposing such actuation, said first and second solenoids exerting substantially equal forces on said element whereby said element remains stationary when both of said so1enoids are energized, and condition-responsive means for deenergizing said second solenoid to permit actuation of said element by said first solenoid.

2. An alarm comprising a first solenoid adapted to be energized from a first electrical circuit, a second solenoid adapted to be energized from a second electrical circuit, said first circuit and said second circuit being separately fused, a vibratory element positioned for actuation by either of said solenoids to sound an alarm, each of said solenoids preventing actuation of said element by the other of said so1enoids when both of said solenoids are energized, and condition-responsive means for deenergizing said second solenoid to permit actuation of said element by said first so1enoid.

3. An alarm comprising a first solenoid adapted to be energized from a first electrical circuit, a second solenoid adapted to be energized from a second electrical circuit, said first circuit and said second circuit being separately fused, a supporting structure for said solenoids, said so1enoids being mounted on said structure with their axes in alignment, a vibratory element positioned between said solenoids and extending transversely of said aligned axes, said solenoids exerting sub stantially equal and oppositeiorces on said element whereby said element is maintained stationary, and condition-responsive means for deenergizing said first solenoid whereby vibration of said element is induced by said second sole- .noid.

4. An alarm comprising a first solenoid adapted .to be energized fromafirst electrical circuit, a second solenoid adapted to be energized from a second electrical circuit, said first circuit and said second circuit being separately fused, a first vibratory' element pivotally mounted adjacent said first'solenoid for actuation thereby, a second vibratoryelement pivotally mounted adjacent said second solenoid for actuation thereby, each of said elements including a portion adapted to engage the other of said elements for maintaining said elements stationary when both of said solenoids are energized, and condition-responsive means for deenergizing said first solenoid whereby said first element is released to permit actuation of said second element by said second solenoid. 5. An alarm comprising a housing, a, pair of solenoidsmounted within said housing, a vibratory element positioned between said solenoids, said solenoids when energized subjecting said element to substantially equal opposed forces whereby said element is maintained stationary, a pair of prongs adapted to be received within a household electrical outlet, said prongs being connected to one'of said solenoids for supplying power from a first electrical circuit to energize said one of said solenoids, a second electrical circuit for supplying power to energize the other of said solenoids, said first circuit and said second circuit being separately fused, and condition-responsive'means for deenergizing said other of said solenoids to permit actuation of said element by said one of said solenoids.

HEBER L. NEWELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 652,734 Coleman June 26, 1900 1,986,613 Warren Jan. 1, 1935 2,456,038 Young Dec. 14, 1948 

